Granted Patent
Utility
US 4,930,866 · App. 07/204,723
Thin film optical variable article and method having gold to green color shift for currency authentication
Inventors:
Peter H. Berning, Roger W. Phillips
Patented Case
View Patent ↗
Granted: Jun 5, 1990
Filed: Jun 10, 1988
Inventors
Peter H. Berning
Roger W. Phillips
Assignee (at issue)
Flex Products, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.